The FAA is restricting the airspace up to 400 feet over four installations in response to an apparent uptick in drone sightings by pilots, reports Military.com. The restrictions go into effect June 1 for Naval Support Activity Monterey, Calif.; Naval Air Station Kingsville, Texas; and Naval Support Activity Orlando, Fla. Existing restrictions were extended around Naval Support Activity South Potomac, Indian Head, Md. The measure is intended to “address the potential threat posed by malicious drone operations by establishing unmanned aircraft system specific airspace restrictions over select, national security sensitive locations,” according to an FAA notice.